Qos and AutoQos for Voip

moreland11moreland11 Member Posts: 24 ■□□□□□□□□□
Trying to get my head around this!
So lets say have 2 6500’s sitting at the collapsed core/distribution where the SVIs and routing lives. We have a numerous 3550’s at the access layer. I am looking to deploy Qos to support a Voip infrastructure. This is a config I believe to be correct.
• Access Points
With Platinum selected on the WLAN controller it will mark the frame with a cos of 6/4.
• Access Switches
Trunk Ports (AP’s and Uplink/Downlink) “Auto Qos Voip Trust”
Access Ports w/ Voice Vlan “Auto Qos Voip Trust Cisco-Phone”
• Core Switches
Trunk Ports – MLS Qos Trust DSCP ?
SVI Interfaces ?????

Once the initial Auto Qos has been run on the switch and cos-to-dscp mappings are in place is there any reason to use “auto qos voip trust” over “mls qos trust dscp”?

This is my understanding of what’s going on. The AP is marking voice traffic with a cos of 6. Switches with auto qos voip trust enabled will remark the cos value of the frame (6) to a dscp mapping (4icon_cool.gif. Trunk ports with dscp trust will keep the dscp value unchanged as it crosses the trunk all the way to the core.

So a few questions I have.

If Mls Qos is enabled on the switch but the trunk port does not have “mls qos trust”, Will the cos/dscp values remarked as 0? Or is it just the cos (802.1p) value over an 802.1Q trunk remarked?

Will the SVI interfaces need Qos configured?

How does the AP mark the traffic? Is it voice traffic that’s marked or does the Phone mark the traffic?

So let’s discuss!
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